Humphrey van Weyden is on board a ferry which is taking him across the San Francisco bay.  He is comfortable and says that he is letting his imagination run loose while the ferry goes across the bay in the fog.  His mind jumps to the division of labor because he is grateful that he does not have to study for hours to learn about navigating the bay.  Instead, he can focus on what he is good at and not have to worry about all the other jobs that get him to and from, or fulfill his needs.  He is recognizing how important it is to have many people good at the very things he is not good at so he can be good at what he does, which is write.

Humphrey is cerebral and he doesn't do physical labor.  This portion of the novel is developing the character for us so that we can contrast it with the very physical Wolf Larsen later in the novel.  While Humphrey believes it is good to have division of labor so he can have an easier life, Larsen believes every man should work long and hard to gain material wealth.